Acta Neurochirurgica

, Volume 151, Issue 5, pp 519–527

Randomized controlled trials in neurosurgery—how good are we?

Neurosurgical Concepts

DOI: 10.1007/s00701-009-0280-y

Cite this article as:
Schöller, K., Licht, S., Tonn, JC. et al. Acta Neurochir (2009) 151: 519. doi:10.1007/s00701-009-0280-y



The strongest evidence in medical clinical literature is represented by randomized controlled trials (RCTs). This study was designed to evaluate neurosurgically relevant RCTs published recently by neurosurgeons.


A literature search in MEDLINE and EMBASE included all clinical studies published up to 30 June 2006. RCTs with neurosurgical relevance published by at least one author with affiliation to a neurosurgical department were selected. The number and characteristics of individual trials were recorded, and the quality of the trials with regard to study design, quality of reporting, and relevance for clinical practice was assessed by two different investigators using a modification of the Scottish Intercollegiate Guidelines Network methodology checklist. Changes of RCT quality over time as well as factors influencing the quality were analyzed.


From the initial search results (MEDLINE n = 3,860, EMBASE n = 3,113 articles), 159 RCTs published by neurosurgeons were extracted for final evaluation. Of the RCTs, 62% have been published since 1995; 52% came from the USA, UK, and Germany. The median RCT sample size was 78 patients and the median follow-up 35.7 weeks. Fifty-two percent of all RCTs were of good, 37% of moderate, and 11% of bad quality, with an improvement over time. RCTs with financial funding and RCTs with a sample size of >78 patients were of significantly better quality. There were no major differences in the rating of the studies between the two investigators.


Only a fraction of neurosurgically relevant literature consists of RCTs, but the quality is satisfying and has significantly improved over the last years. An adequate sample size and sufficient financial support seem to be of substantial importance with regard to the quality of the study. Our data also show that by using a standardized checklist, the quality of trials can be reliably assessed by observers of different experience and educational levels.


Randomized controlled trialClinical trialEvidence-based medicineNeurosurgery

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of NeurosurgeryUniversity of Munich Medical Center–Grosshadern, Ludwig-Maximilians-UniversityMunichGermany
  2. 2.Department of NeurosurgeryUniversity of Munich Medical CenterMunichGermany